         (html [:div.home.page
                [:nav.home-nav {:class (concat
                                        (when (:header-logo-visible state) ["logo-visible"])
-                                       (when (:header-cta-visible state) ["cta-visible"]))}
+                                       (when (:header-cta-visible state) ["cta-visible"])
+                                       (when (:header-bkg-visible state) ["bkg-visible"]))}
                 [:a.promo "What is Continuous Integration?"]
                 [:a.login "Log In"]
                 (om/build drawings/logo-circleci app)
                 [:a.action "Sign Up Free"]]
-               [:section.home-prolog
+               [:section.home-prolog {:ref "nav-bkg"}
                 [:a.home-action {:role "button"
                                  :ref "cta"}
                  "Sign Up Free"]

(defn mount-header-logo-scroll [owner]
  (let [logo (om/get-node owner "center-logo")
        cta (om/get-node owner "cta")
        scroll-callback #(do
                           (om/set-state! owner [:header-logo-visible] (neg? (.-bottom (.getBoundingClientRect logo))))
                           (om/set-state! owner [:header-cta-visible] (neg? (.-bottom (.getBoundingClientRect cta)))))]
    (om/set-state! owner [:browser-resize-key]
                   (goog.events/listen
                    (sel1 (om/get-shared owner [:target]) ".app-main")

    (init-state [_]
      {:header-logo-visible false
       :header-cta-visible false
       :header-bkg-visible false
       :scroll-ch (chan (sliding-buffer 1))})
    om/IRenderState
    (render-state [_ state]
